Devices, systems, and methods for testing crash avoidance technologies

ABSTRACT

A Guided Soft Target (GST) system and method provides a versatile test system and methodology for the evaluation of various crash avoidance technologies. This system and method can be used to replicate the pre-crash motions of the CP in a wide variety of crash scenarios while minimizing physical risk, all while consistently providing radar and other sensor signatures substantially identical to that of the item being simulated. The GST system in various example embodiments may comprise a soft target vehicle or pedestrian form removably attached to a programmable, autonomously guided, self-propelled Dynamic Motion Element (DME), which may be operated in connection with a wireless computer network operating on a plurality of complimentary communication networks. Specific DME geometries are provided to minimize ride disturbance and observability by radar and other sensors. Computer controlled DME braking systems are disclosed as well as break-away and retractable antenna systems.

1.0 CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority as a continuation-in-part of U.S.patent application Ser. No. 13/357,526 entitled “System and Method forTesting Crash Avoidance Technologies” filed Jan. 24, 2012 by JosephKelly et al, as a non provisional of U.S. Patent Application No.61/507,539 entitled “Guided Soft Target For Full Scale Advanced CrashAvoidance Technology Testing” filed on Jul. 13, 2011 by Joseph Kelly etal, as a non-provisional of U.S. Patent Application No. 61/578,452entitled “Guided Soft Target For Full Scale Advanced Crash AvoidanceTechnology Testing” filed on Dec. 21, 2011 filed by Joseph Kelly et al,as a non-provisional of U.S. Patent Application No. 61/621,597 entitled“Collision Partner, System and Method” filed on Apr. 9, 2012 by JosephKelly et al, and as a non-provisional of U.S. Patent Application No.61/639,745 entitled “Devices, Systems, And Methods For Testing CrashAvoidance Technologies” filed on Apr. 27, 2012 by Joseph Kelly et al.Each of these patent applications is incorporated herein in theirentirety.

2.0 TECHNICAL FIELD

The present invention relates to devices, systems, and methods fortesting crash avoidance technologies.

3.0 BACKGROUND

As Advanced Crash Avoidance Technologies (ACATs) such as ForwardCollision Warning (FCW), Crash Imminent Braking Systems and otheradvanced technologies continue to be developed, the need for full-scaletest methodologies that can minimize hazards to test personnel anddamage to equipment has rapidly increased. Evaluating such ACAT systemspresents many challenges. For example, the evaluation system should beable to deliver a potential Soft Collision Partner (Soft CP) reliablyand precisely along a trajectory that would ultimately result in a crashin a variety of configurations, such as rear-ends, head-ons, crossingpaths, and sideswipes. Additionally, the Soft Collision Partner shouldnot pose a substantial physical risk to the test driver, other testpersonnel, equipment, or to subject vehicles in the event that thecollision is not avoided. This challenge has been difficult to address.Third, the Soft CP should appear to the subject vehicle as the actualitem being simulated, such as a motor vehicle, a pedestrian, or otherobject. For example, the Soft CP should provide a consistent signaturefor radar and other sensors to the various subject vehicles,substantially identical to that of the item being simulated. It would bealso advantageous for the Soft CP to be inexpensive and repeatablyreusable with a minimum of time and effort.

Past attempts to provide a suitable Soft CP include: a balloon car, anexample of which is depicted in FIG. 13 (the “balloon car”); a rear-endtarget specified by the National Highway Traffic Safety Administration(NHTSA); an example of which is depicted in FIG. 14 (the “NHTSAcar-rear”); and a cushioned crashed target provided by Anthony BestDynamics (ABD), an example of which, partially cut away to show internalstructure, is depicted in FIG. 15 (the “ABD car”). All these priordesigns have limitations. The balloon car is subject to damage,including bursting, when impacted at higher speeds. Additionally, theballoon car tends to exhibit aerodynamic flutter when moving through theair, which can confuse the sensors on the subject vehicle. The NHTSAcar-rear can only be used for rear-end collision testing, and due to itsunyielding design can cause minor damage to the subject vehicle athigher speeds. The ABD car cannot be driven through or over due to thelarge drive system 1505 in the middle of the car as shown in FIG. 15.The relatively heavy ABD car must be pushed out of the way during animpact, creating large forces on the subject vehicle at high speeds, andtherefore cannot be used for impact speeds over about 50 kilometers perhour. Additionally, prior art Soft CP's have lacked the steering andbraking performance of the vehicles they are simulating, limiting theirusefulness in generating real-world data.

4.0 SUMMARY

4.1 Guided Soft Target System and Method

A Guided Soft Target (GST) system and method is provided that overcomesthese challenges and more by providing a versatile test system andmethodology for the evaluation of various crash avoidance technologies.This system and method can be used to replicate the pre-crash motions ofthe Soft CP in a wide variety of crash scenarios while minimizingphysical risk, all while consistently providing an appearance andsignature to radar and other sensors substantially identical to that ofthe item being simulated. The GST system in various example embodimentsmay comprise a soft target vehicle or pedestrian form removably attachedto a programmable, autonomously guided, self-propelled Dynamic MotionElement (DME), which may be operated in connection with a wirelesscomputer network. The Soft Car or Soft Pedestrian is intended to be arealistic representation of a Soft CP for both the driver and the systemunder evaluation, and the DME serves as a means of conveyance for theSoft Car such that the motions of the Soft CP are realistic. As a fullyautonomous vehicle, the GST can coordinate its motions with the subjectvehicle during the pre-crash phase such that the initial conditions ofthe crash phase are replicated from run to run. At the instant that theACAT or subject vehicle driver begins to respond to the conflict, incertain embodiments the GST can automatically switch to a mode in whichits speed and course are no longer coordinated with the position of thesubject vehicle, but instead are such that the GST follows apredetermined speed/time/distance trajectory to a target ground-fixedimpact point. This enables the analyst to determine the effect of theACAT system on the subject vehicle's potential impact with, or avoidanceof, the GST as it arrives at the target impact point (e.g., the changein such indices as the “resultant relative velocity at minimum distance”(RRVMD), minimum distance (MD), etc.).

The developed car and pedestrian GST system has versatile as well asrobust capabilities, and provides test engineers with the flexibilityand low test cycle time necessary for development and testing of ACATs.The GST system can replicate virtually any type of collision between theGST and the subject vehicle, including rear-ends, head-ons, crossingpaths, sideswipes and pedestrian collisions. The Soft Car or SoftPedestrian bodies can be constructed with a wide variety ofthree-dimensional shapes and sizes, allowing the ACAT developer orevaluator to measure the effect of the system across a range ofCollision Partners. These Collision Partner soft bodies can be re-usedand reassembled quickly (usually within 10 minutes), and theself-propelled-and-guided DME, encased in a hardened, low-profile,drive-over shell, can be quickly repositioned, allowing the test team toevaluate large numbers of different, realistic scenarios with multiplerepeats.

The development of a test methodology, based on the GST system, allowsfor the evaluation of diverse ACATs covering a wide range of crash andpre-crash conflict scenarios, effectively exercising the various modesand operating conditions of the ACAT. The ability to guide and propel aconflict partner on complex trajectories through the time of collisionenables the evaluation of not only collision avoidance but alsocollision mitigation, vehicle-to-vehicle and vehicle-to-infrastructuretechnologies. Further, the data collected for both the subject vehicleand GST in the course of such evaluations allows detailed analysis ofsystem response and effectiveness, including its effects on collisionavoidance (i.e., minimum distance) as well as its effects on collisionseverity (i.e., closing speed, contact points, relative heading angle)when a collision occurs.

The inventors are unaware of any prior methods or test systems in whichboth the subject vehicle and Collision Partner move realistically atrelatively high speeds up to and through the point of impact, whileminimizing physical risk to test personnel and equipment. Further, thespecific geometries for the DME that have been found to both increasesafety while minimizing the observability of the DME by radar and othersensors are believed to be new and nonobvious. As noted by manyresearchers, the development of advanced crash avoidance technologies(ACATs) with increased capabilities offers substantial potential forfuture reductions in vehicle-related collisions, injuries, andfatalities.

4.1 Low-Profile Dynamic Motion Element

Specific geometries for the DME have been discovered that minimize therisk of the DME flipping up and hitting or otherwise damaging ordisrupting the ride of typical subject vehicles during impact of thesubject vehicles with the GST, all while minimizing the DME's visibilityto the subject vehicle's radar and other sensors.

4.2 Soft Collision Partner System and Method

Also provided is a new and improved Soft CP, system and method thatprovides an inexpensive and easy way to assemble a structure capable ofclosely simulating the rigid appearance and radar and other sensorsignatures of items such as a motor vehicle, a pedestrian, or otherobject, while providing a safe and easily reusable target for high-speedsubject vehicles used to evaluate crash avoidance technologies. ExampleSoft CP's designed, manufactured and assembled according to the presentinvention can handle impacts at relative speeds over 110 kilometers perhour without damage to the Soft CP or the subject vehicle. Theinterlocking internal structure of the present Soft CP's providessufficient support to make them aerodynamically stable, limiting oreliminating aerodynamic flutter. The present Soft CP's can be easilymade to resemble the simulated item from all directions, allowing thesubject vehicle to approach from any angle. Instead of remaining in onepiece that needs to be pushed out of the way, the present Soft CP'sreduce impact forces by breaking apart into separate, light-weight,easily-reassemblable panels. The present Soft CP's may be adapted foruse atop low-profile drive systems that are driven-over by the subjectvehicle, instead of pushed out of the way by the subject vehicle.

The present Soft CP, system and method can be used in conjunction with aGST system to replicate the pre-crash motions of a person, car, or otheritem in a wide variety of crash scenarios while minimizing physicalrisk, all while consistently providing radar and other sensor signaturessubstantially identical to that of the item being simulated. Thepresently-disclosed GST systems or any other suitable GST systems may beused in connection with the present Soft CP, system and method.

Other aspects of the invention are disclosed herein as discussed in thefollowing Drawings and Detailed Description.

5.0 BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the followingfigures. The components within the figures are not necessarily to scale,emphasis instead being placed on clearly illustrating example aspects ofthe invention. In the figures, like reference numerals designatecorresponding parts throughout the different views. It will beunderstood that certain components and details may not appear in thefigures to assist in more clearly describing the invention.

FIG. 1 is a top isometric view of an example DME according to variousexample embodiments.

FIG. 2 is a bottom isometric view of the example DME of FIG. 1 accordingto various example embodiments.

FIG. 3 is a top plan view of the example DME of FIG. 1 according tovarious example embodiments.

FIG. 4 is a left side elevation view of the example DME of FIG. 1according to various example embodiments.

FIG. 5 is a rear side elevation view of the example DME of FIG. 1according to various example embodiments.

FIG. 6A is a front perspective view of an example light passengervehicle GST according to various example embodiments.

FIG. 6B is a back perspective view of the example light passengervehicle GST of FIG. 6A according to various example embodiments.

FIG. 6C is a side elevation view of the example light passenger vehicleGST of FIG. 6A, shown before being impacted by an example subjectvehicle, according to various example embodiments.

FIG. 6D is a side elevation view of the example light passenger vehicleGST of FIG. 6A, shown while being impacted by an example subjectvehicle, according to various example embodiments.

FIG. 7 is a front perspective view of an example pedestrian GSTaccording to various example embodiments.

FIG. 8 is a diagram showing certain elements of an example GST systemarchitecture according to various example embodiments.

FIG. 9 is a diagram of an example computerized braking system for a DMEshowing certain example features.

FIG. 10A is a sectional side elevation view of a break-away antennasystem according to various example embodiments, shown in the normallyinstalled position.

FIG. 10B is a section side elevation view of the break-away antennasystem of FIG. 10A, shown during break-away, for instance during impact.

FIG. 11A is a sectional side elevation view of a first retractableantenna system according to various example embodiments, shown in thenormally protruding position.

FIG. 11B is a section side elevation view of the first retractableantenna system of FIG. 11A, shown in the retracted position, forinstance during impact.

FIG. 12A is a sectional side elevation view of a second retractableantenna system according to various example embodiments, shown in thenormally protruding position.

FIG. 12B is a section side elevation view of the second retractableantenna system of FIG. 12A, shown in a first retracted position, forinstance during impact from a first direction.

FIG. 12C is a section side elevation view of the second retractableantenna system of FIG. 12A, shown in a second retracted position, forinstance during impact from a second direction.

FIG. 13 is a side elevation view of an example prior art “balloon car”Soft Collision Partner.

FIG. 14 is a back perspective view of an example prior art “NHTSAcar-rear” Soft Collision Partner.

FIG. 15 is a front perspective view of an example prior art “ABD car”Soft Collision Partner.

FIG. 16 is a side perspective view of an example Soft CP soft body andsystem according to certain example embodiments, with the outermostfabric skin removed, mounted on a DME.

FIG. 17 is a side perspective view of an example Soft CP soft body andsystem according to certain example embodiments, with the outermostfabric skin removed, illustrating the mounting to a DME.

FIG. 18 is an exploded view of an example Soft CP soft body and systemaccording to certain example embodiments, with the outermost fabric skinremoved.

FIG. 19 is a side perspective of the example Soft CP soft body andsystem partially assembled, according to certain example embodimentswith the outermost fabric skin removed, mounted to a DME.

FIG. 20 is a side perspective of the example Soft CP soft body andsystem partially assembled (although more fully assembled than FIG. 19),according to certain example embodiments with the outermost fabric skinremoved, mounted to a DME.

FIG. 21 is a side perspective of the example Soft CP soft body andsystem partially assembled (although more fully assembled than FIG. 20),according to certain example embodiments with the outermost fabric skinremoved, mounted to a DME.

FIG. 22A is a front perspective view of the example Soft CP soft bodyand system of FIGS. 16-21 fully assembled with the outermost fabric skinpartially peeled back.

FIG. 22B is a front perspective view of the example Soft CP soft bodyand system of FIGS. 16-21 fully assembled with the outermost fabric skincompletely installed.

FIG. 23 is a top plan view of example panels of the example Soft CP softbody and system of FIG. 22, showing dimensions for certain exampleembodiments.

FIG. 24 is a top plan view of example panel numbers 0 and 1 of theexample Soft CP soft body and system of FIG. 22A, showing dimensions forcertain example embodiments.

FIG. 25 is a top plan view of example panel numbers 2 and 3 of theexample Soft CP soft body and system of FIG. 22A, showing dimensions forcertain example embodiments.

FIG. 26 is a top plan view of example panel numbers 4 and 5 of theexample Soft CP soft body and system of FIG. 22A, showing dimensions forcertain example embodiments.

FIG. 27 is a top plan view of example panel numbers 6 and 7 of theexample Soft CP soft body and system of FIG. 22A, showing dimensions forcertain example embodiments.

FIG. 28 is a top plan view of example panels of the example Soft CP softbody and system of FIG. 22A, showing dimensions for certain exampleembodiments.

FIG. 29 is a side elevation view of the example Soft CP soft body andsystem of FIG. 22A, showing possible locations for the example panelsshown in FIGS. 16 through 22, further including dimensions for certainexample embodiments.

FIG. 30 is an end view of the intersection of example removablyconnectable panels of an example Soft CP soft body and system accordingto certain example embodiments.

FIG. 31 is an end view of the intersection of example removablyconnectable fabric skin and panel of an example Soft CP soft body andsystem according to certain example embodiments.

FIG. 32 is a side elevation view of the example Soft CP soft body andsystem of FIG. 22A fully assembled atop a DME according to certainexample embodiments, shown in use and about to be impacted from thefront by an example subject vehicle according to certain exampleembodiments.

FIG. 33 is a side elevation view of the example Soft CP soft body andsystem of FIG. 22A, shown in use while being impacted from the front byan example subject vehicle according to certain example embodiments.

FIG. 34 is a side elevation view of the example Soft CP soft body andsystem of FIG. 22A fully assembled atop a DME according to certainexample embodiments, shown in use and about to be impacted from the rearby an example subject vehicle according to certain example embodiments.

FIG. 35 is a side elevation view of the example Soft CP soft body andsystem of FIG. 22A, shown in use while being impacted from the rear byan example subject vehicle according to certain example embodiments.

6.0 DETAILED DESCRIPTION

Following is a non-limiting written description of example embodimentsillustrating various aspects of the invention. These examples areprovided to enable a person of ordinary skill in the art to practice thefull scope of the invention without having to engage in an undue amountof experimentation. As will be apparent to persons skilled in the art,further modifications and adaptations can be made without departing fromthe spirit and scope of the invention, which is limited only by theclaims.

6.1 Definitions

The following acronyms will be used throughout this description:Advanced Crash Avoidance Technologies (ACATs); Guided Soft Target (GST);Dynamic Motion Element (DME); Forward Collision Warning (FCW); CrashImminent Braking Systems (CIBS); Soft Collision Partner (Soft CP);Resultant Relative Velocity at Minimum Distance (RRVMD); MinimumDistance (MD); Wireless Local Area Network (WLAN); Guidance, Navigationand Control (GNC) computations; Differential GPS (DGPS); GroundClearance (GC).

6.2 Example Dynamic Motion Elements

The DME 100, examples of which are shown in FIGS. 1-5, is at the heartof the GST system. The DME 100 is a completely self-contained,un-tethered, relatively high-speed, mobile platform for the SoftCollision Partner 600, and which performs all Guidance, Navigation andControl (GNC) computations, and is capable of being driven over by thesubject vehicle 650 without damage to itself or the subject vehicle 650.

Positional measurements, which are the primary measurement used intypical GNC computations, are achieved via the on-board DGPS receiver.Other inputs to the GNC computations may include the yaw rate andheading angle, as measured by an electronic compass.

The DME 100 may incorporate a pair of brushless DC motors to drive, forinstance, the rear wheel(s) 220, while steering of the front wheel(s)200 may be accomplished via a brushless DC position control servo, forexample. Wheels 200, 220 means the wheel assembly, including the tire orother material that contacts the ground.

The construction of the DME 100 facilitates mounting, housing andprotection of all system components, including for example the computer,sensors, actuators, batteries, and power supplies. The DME 100 may beconstructed primarily of aluminum, steel, or any suitably strongmaterial(s), and may utilize an egg-crate, honeycomb, or similar typeinternal structure (not shown) with exterior armor cladding. Withreference to FIG. 1, the DME 100 may include a front side 75, a rear orback side 70, a left side 80 (which would be a driver's side if the DMEwas an automobile in the U.S.), and a right side 85 (which would be apassenger's side if the DME was an automobile in the U.S.). The exteriorarmor cladding may comprise a top surface 10 and a bottom surface 20(shown in FIG. 2), a front upper surface 40, a rear upper surface 30, aleft side upper surface 50, and a right side upper surface 60. Other orfewer surfaces may be employed in various other embodiments. As shown inFIG. 2, wheels may extend downward below bottom surface 20. In oneexample embodiment, wheels may comprise one or more non-steered wheels220 and one or more steered wheels 200. Any or all of the wheels may besteered, and any or all of the wheels may be driven. In one exampleembodiment discussed herein, the rear wheels 220 (which may comprise twowheels adjacent to each other) are driven and the front wheels 200 aresteered, that is, at least partially rotatable about a substantiallyvertical axis (i.e., an axis substantially perpendicular to bottomsurface 20).

6.3 Examples of Low-Profile Dynamic Motion Elements

As illustrated in the example embodiments shown in FIGS. 3, 4 and 5, thelarge horizontal dimensions L, W, and small height H1, H2, of DME 100create shallow approach angles α1, α2, minimizing the load impartedhorizontally when driven over by the subject vehicle 650, for instanceas shown in FIG. 6D. These dimensions also minimize the potential forcontact between the subject vehicle 650 structure (e.g., undercarriageor bumpers) and the DME 100 structure, for instance by the DME flippingup against the subject vehicle 650 when the GST is impacted by thesubject vehicle 650.

With reference to FIG. 3, to avoid “flip up” of the DME 100 under thesubject vehicle 650, dimension L may optimally be selected to be greaterthan or equal to the wheelbase of the typical subject vehicle 650 (i.e.,the distance from the centerline of the front axle to the centerline ofthe rear axle of the subject vehicle 650). To minimize the effect of theDME 100 on the radar and other sensor signatures of the GST, dimension Lmay be selected to be less than the overall length of the soft body 600.In a first embodiment, dimension L may be selected to be about 2000millimeters, plus or minus 300 millimeters, for instance for use withsmaller vehicles. In a second embodiment, dimension L may be selected tobe about 2600 millimeters, plus or minus 300 millimeters, for instancefor use with larger vehicles. In a third embodiment, dimension L may beselected to be about 3200 millimeters, plus or minus 300 millimeters,for instance for use with long vehicles. In a fourth embodiment,dimension L may be selected to be about 4000 millimeters, plus or minus500 millimeters, for instance for use with very long wheel-base vehiclessuch as crew cab long bed pick-up trucks.

Also to avoid “flip up” of the DME 100 under the subject vehicle 650,dimension W may optimally be selected to be greater than or equal to thetrack width of the typical subject vehicle 650 (i.e., the distance fromthe center of the driver's side tires to the center of the passenger'sside tires of the subject vehicle 650). To minimize the effect of theDME 100 on the radar and other sensor signatures of the GST, dimension Wmay be selected to be less than the overall width of the soft body 600.In the first embodiment, dimension W may be selected to be about 1200millimeters, plus or minus 300 millimeters, for instance for use withsmaller vehicles. In the second embodiment, dimension W may be selectedto be about 1800 millimeters, plus or minus 300 millimeters, forinstance for use with larger vehicles. In the third and fourthembodiment, dimension W may be selected to be about 2600 millimeters,plus or minus 500 millimeters, for instance for use with very largevehicles such as heavy trucks.

Any other lengths for dimensions L and W may be used as long as theycoordinate with each other and dimension H1 to result in angles α1, α2,falling within appropriate ranges, discussed below. For example, in theexample embodiments shown in FIGS. 6A-6D where the subject vehicle 650was a late model Honda Accord, dimension L was selected to be about 2790millimeters, dimension W was selected to be about 1520 millimeters, andwas selected to be about 100 millimeters (plus or minus 10 millimeters).Dimensions L and W can be smaller than the first embodiment where theGST is a smaller object such as a pedestrian 700, such as in the exampleDME 100′ shown in FIG. 7. Finally, dimensions L and W could be scaled upbeyond those provided in the fourth embodiment to work with even largersubject vehicles 650.

With reference to FIGS. 4 and 5, H1 is the vertical dimension from thebottom 20 to the top 10 of DME 100. H2 is the vertical dimension fromthe ground 400 (ground 400 meaning the surface of the road or othersurface on which the DME 100 travels) to the top 10 of DME 100. Tominimize disturbance to the ride of the subject vehicle 650, H2 ispreferably as small as possible. Minimizing H2 tends to preventdiscomfort to drivers and potential accidents, and minimizes chances ofdamage to the subject vehicle 650 or instrumentation attached thereto,airbag deployment, and the like. H2 is also preferably minimized toprevent the chance of the DME 100 striking the bottom of the subjectvehicle 650 even when the DME 100 does not “flip up.” Minimizing H2requires minimizing both H1 and Ground Clearance (GC). The GroundClearance or GC of the DME 100 is the vertical distance from the ground400 to the bottom 20 of DME 100, and is calculated by subtracting H1from H2. Nominal Ground Clearances that have been found to workacceptably include distances of about 12 to 19 millimeters, and at leastabout 5 millimeters but preferably no more than 50 millimeters. In theembodiments described herein H1 has been minimized to about 100millimeters, plus or minus 10 millimeters. Using other materials andsmaller components could potentially reduce H1 even further. Addingtypical Ground Clearance of about 12 to 19 millimeters to H1 of about 90to 110 millimeters yields an overall H2 of about 100 to 130 millimeters,give or take a couple millimeters.

H1 and H2 are minimized not only to minimize ride disturbance of thesubject vehicle 650 and to prevent contact of the DME 100 to theundercarriage of the subject vehicle 650, but H1 and H2 are alsoselected to coordinate with dimensions L and W so that angles α1, α2,are minimized and fall within appropriate ranges. As shown in FIG. 4,angle α1 is the angle between the ground 400 and the upper back surface30 of the DME 100, or between the ground 400 and the upper front surface40 of the DME 100, or both. In typical embodiments angle α1 is the samefor both the front and back upper surfaces, 30, 40, of DME 100, however,angle α1 can differ between the front and rear the upper surfaces, 30,40, of the DME 100 if the upper surfaces of DME 100 are not symmetricalabout a central latitudinally-extending vertical plane. As shown in FIG.5, angle α2 is the angle between the ground 400 and the upper left sidesurface 50 of the DME 100, or between the ground 400 and the upper rightside surface 60 of the DME 100, or both. In typical embodiments angle α2is the same for both the left and right upper surfaces, 50, 60, of DME100, however, angle α2 can differ between the left and right uppersurfaces, 50, 60, of the DME 100 if the upper surfaces of DME 100 arenot symmetrical about a central longitudinally-extending vertical plane.Importantly, while upper surfaces 30, 40, 50 and 60 are shown assubstantially flat planes each comprising multiple panels, any or all ofupper surfaces 30, 40, 50 and 60 may be curved and not flat, orpartially curved and partially flat. Where any or all of upper surfaces30, 40, 50 and 60 are curved and not flat, or are partially curved andpartially flat, angles α1, α2, may be measured between the ground 400and the steepest portion of any of corresponding upper surfaces 30, 40,50 and 60. For purposes of this measurement the steepness or angle of acurve at a given point is measured by a line tangent to the curve atthat point, i.e., the first derivative thereof, as is known in the art.

Like H2, angles α1, α2, are minimized to minimize ride disturbance ofthe subject vehicle 650 and to make the subject vehicle 650 travel assmoothly as possible over the DME 100. In various embodiments α1 and α2may each be selected to be between about 4 degrees to about 45 degrees.In one example embodiment α1 is selected to be about 4 degrees while α2is selected to be about 12 degrees.

ACATs often use various types of radar and other sensors to detectobstacles in the path of the subject vehicle 650, and to alert thedriver or take evasive action or some other action if the ACATdetermines that the subject vehicle is likely to collide with such anobstacle. Accordingly, radar and other sensor systems have often beendesigned not to be triggered by items normally in the roadway, such asraised manhole covers and highway construction plates, or at leastdistinguish between such items close to the roadway and larger items,such as another vehicle. Still, some ACAT systems may trigger an alarmor some other type of response if they detect something in the roadwayas large as a DME 100. For this reason, it has been discovered to beimportant to minimize the observability of the DME 100 by radar andother sensors. Additionally, to achieve accurate results when testingACATs against GSTs that simulate objects such as vehicles, pedestrians,or other objects, it is helpful to minimize the distortion of the radaror other sensor signatures of the simulated soft vehicle, pedestrian, orother object that is caused by the presence of the DME 100. For thisseparate reason it has been discovered to be important to minimize theobservability of the DME 100 by radar and other sensors.

The geometries disclosed herein for DME 100 have been found toeffectively minimize the observability of the DME 100 by radar and othersensors. While all of the geometries disclosed above are useful forminimizing the observability of the DME 100 by radar and other sensors,it has been discovered that the following characteristics areindividually and together particularly helpful in minimizing theobservability of the DME 100 by radar and other sensors: H2 less thanabout 350 millimeters, and preferably not more than about 300millimeters; α1 and α2 not more than about 45 degrees, and L and Wdimensions within the corresponding length and width dimensions of theSoft Collision Partner 600 (shown in FIGS. 6A-6D) or other item that ismounted to the DME 100 to create the GST. For example, for a typicalSoft Collision Partner 600 the L and W dimensions may be not more thanabout 4880 millimeters for L and about 1830 millimeters for W. Other Land W dimensions may be appropriate for other GSTs, as will be apparentto persons of skill in the art upon reviewing this disclosure.

The DME 100 may also employ retractable running gear, such that thestructure “squats” onto the road surface when driven over by the subjectvehicle 650. This creates a direct load path from the tires of thesubject vehicle 650 to the ground 400 without passing through the GSTwheels 200, 220 and associated suspension components. This may beaccomplished through the use of pneumatic actuators that create justenough force to deploy the wheels 200, 220 and lift the DME 100 to itsmaximum ground clearance (H2 minus H1), for instance approximately onecentimeter. In these embodiments the DME structure 100 can squatpassively under the loading of the tires of the subject vehicle 650,without requiring dynamic actuation.

6.4 Example Dynamic Motion Element Braking Systems and Methods

The DME structure 100 may be provided with front and/or rear brakes,such as disc brakes, to provide braking capability during a conflictscenario or to bring the DME 100 to a stop after a scenario. The brakesmay be actuated autonomously by the DME 100 according to apre-programmed trajectory or other conditions or by a test engineer viaa radio transmitter in order to perform an emergency-stop, for example.

FIG. 9 illustrates an example braking system 900 adapted for use with aDME 100. Example braking system 900 may be controlled by a computer 910,such as the GST Computer, which may in certain embodiments sendindependent braking command signals, such as a front brake command 912and rear brake command 914. In other embodiments commands may be sent toeach wheel brake individually, or to a sub-combination of the wheelbrakes, or a single command may be sent to all the wheel brakes at once.The front and rear brake commands 912, 914, may in certain embodimentsactivate front and rear brake servos, 920, 925, respectively, which mayin turn be mechanically coupled by mechanical actuators 922, 927, tofront and rear master cylinders 930, 935. Front and rear mastercylinders 930, 935 may be hydraulically and/or pneumatically connectedby lines 932, 937, to brake actuators 940, 945, such as disc brakecalipers. The brake actuators 940, 945, then actuate brakes on the frontand rear wheels 950, 955, such as disc brakes.

For increased safety a redundant, parallel braking system may beprovided, such as remotely controlled brake command system 960 that uponactivation sends an independent braking command to a brake servo, suchas an independent brake servo 965. The independent brake servo 965 maybe mechanically coupled by one or more mechanical actuators 967 to rearmaster cylinder 935, to brake the rear wheels 950. It will be understoodthat this is just one example architecture for a redundant, parallelbraking system. For instance, in other embodiments the remotelycontrolled brake command system 960 may send braking commands to any orall of the brake servos.

In various example embodiments each wheel, 950, 955, of the DME 100 maybe equipped with its own brake rotor and caliper 940, 945. The rearbrake system may have a separate hydraulic master cylinder 935 from thefront master cylinder 930 for the front brake system, or they may usethe same master cylinder, which may have one or more hydraulicreservoirs dedicated to separate hydraulic lines 932, 937, as in atypical passenger vehicle. Each master cylinder 930, 935 may beindependently actuated by its own electric servo motor 920, 925. Thefront and/or rear brakes may be controlled by a computer 910, ormanually, remotely controlled by a remotely controlled brake commandsystem 960. In certain embodiments the brake disc(s) for the non-drivenwheel(s) are attached to the hubs of the non-driven wheel(s), while thebrake disc(s) for the driven wheels may be attached to the driveline,such as a motor-driven pulley (not shown), and apply braking to the rearwheels via the driveline, such as via drive belts.

Typically all brakes are automatically applied by the computer 910 ifcommunication to the operator's station 850 is lost. Automaticapplication of brakes upon loss of communication increases safety, as doredundant brake systems. The brake servos may also be adapted to benormally actuated, such that they automatically activate the brakes whenelectrical power is lost. Additionally, wheel rotation sensors, controlfeedback loops and processors may be included to provide additionalfeatures such as anti-lock brakes, stability control, and the like.Stability control, for instance, is a computerized technology that canimprove the DME 100's stability by detecting and reducing excessive yawmotion by applying braking and/or traction forces. When stabilitycontrol systems detect excessive yaw motion, they can automaticallyapply the brakes on various specific wheels to help reduce excessive yawmotion thereby helping to “steer” the vehicle along the intended path.Braking may be automatically applied to wheels individually, such as theouter front wheel to counter oversteer or the inner rear wheel tocounter understeer. Stability control systems may also reduce driveforces until control is regained.

Combining some or all of these features provides increased sustainedbraking capability limited only by tire traction, allowing the DME 100to replicate real-world vehicle motions and levels of deceleration. TheDME 100 is designed to coordinate movement with the subject vehicle,which requires that it be able to accurately follow the speed profile(including decelerations and turns) of the collision partner.Computer-controlled adjustable brake bias between front and rear brakes,or between any or all brakes, allows full utilization of potentialbraking power and control. Computer-controlled adjustable brake biasalso obviates the need for mechanical adjustments, such as whiffletreelinkage to adjust brake bias. It also allows the brake bias to beadjusted automatically in real-time based on the state of the DME 100,for instance due to changing maneuvers, different weight and size SoftCP 600 bodies, changing road surface conditions, changing winds, and thelike.

6.5 Example Break-Away Antenna Systems

The DME 100 may include various antennas so that the subject vehicle650, base station 850, and/or others may communicate with the DME 100.However, the presence of a soft car body 600 on top of the DME 100 maytend to cover-up one or more of the antennas on the DME 100, limitingthe range of the antennas or rendering them inoperable. Additionally,antennas attached to and protruding from the DME 100 may be broken whenthe DME 100 is impacted and run over by a subject vehicle 650. Providedin FIGS. 10A and 10B is an example break-away antenna system 1000 thataddresses all of these issues. In various example embodiments antennasystem 1000 may include one or more antennas 1010 attached with and/orprotruding from the exterior 1060 of the body of the soft car 600 sothat the base station 850 and/or others may communicate with the DME 100through the antennas 1010. The one or more antennas 1010 may include anouter break-away connection 1020 proximate the body 1060 and comprisingtwo removably-connectable connectors 1022, 1024 connecting the antenna1010 to an outer antenna wire 1026. The outer antenna wire 1026 may beconnected with an inner break-away connection 1030 proximate theexterior surface 1050 of the DME 100 and comprising tworemovably-connectable connectors 1032, 1034 connecting the outer antennawire 1026 to an inner antenna wire 1036. To protect the connector 1034and wire 1036 in the event the DME 100 is run over by a subject vehicle650, the connector 1034 and wire 1036 may be recessed in a cup-like orsimilar structure 1040 below the outer surface 1050 of the exterior ofthe DME 100. The connector 1034 and wire 1036 may also be left with someslack inside the cup 1040 to facilitate safe disconnection of theconnectors 1032, 1034 during impact, as depicted in FIG. 10B.

FIG. 10B depicts the example antenna system 1000 after impact 1000′,when the soft car body 600 has been ripped away from the DME 100 due tobeing impacted by a subject vehicle 650. In this example, the outerantenna wires 1026 and inner antenna wires 1036 were pulled taut whenthe exterior 1060 of the body of the soft car 600 was ripped away fromthe DME 100 by impact with a subject vehicle 650. The resulting tensileforce in the wires 1026, 1036 was sufficient to disengage connectableconnectors 1022, 1024, 1032, and 1034 (though in certain instances onlyconnectable connectors 1022, 1024 or connectable connectors 1032, 1034might be disengaged). The slack in the wires 1026, 1036 allowed theremovably-connectable connectors 1032, 1034 to substantially align withwire 1026 prior to applying tensile force to removably-connectableconnectors 1032, 1034, which increases the chances of successfuldisconnection and decreases the chances of damage to the connectors1032, 1034. The connector 1034 and inner wire 1036 remained inside thecup 1040 beneath the exterior surface 1050 of the DME 100, and were thussafe from being damaged by the subject vehicle 650. The antennas 1010and other components are typically removed with the body of the soft car600 and can be reused by re-connecting connectors 1022, 1024 and 1032,1034.

Any removably-connectable electrical RF connectors may be used forconnectors 1022, 1024 and 1032, 1034, preferably ones adapted to bereusable. One suitable connector may be created by removing the lockingbayonets from a standard BNC-type connector. In certain exampleembodiments connectors 1024, 1034 can be formed from either a male BNCor male TNC connector with the locking structures removed. Connectors1022, 1032 then slide into connectors 1024, 1034 and remain engagedduring normal use but can be easily pulled out during an impact. Theconnectors 1020, 1030 will withstand and remain connected for tensileforces of at least 0.1 pounds, and will disconnect when subjected totensile forces greater than 0.5 pounds. Standard connectors may befurther modified to remove exterior edges that may catch on adjacentsurfaces during impact. This can be accomplished with either a taperedcollar composed of a low-friction material or by re-shaping theconnector housing, for instance. In each case the communication betweenthe DME 100 and the subject vehicle 650, and/or base station 850, isreliable but the antennas 1010 are also able to disconnect upon impactwith the subject vehicle 650. The use of the removably-connectableconnectors thus improves reliability and reusability.

6.6 Example Retractable Antenna Systems

Certain antenna types may be better protected upon impact by a subjectvehicle 650 by being refracted into the body of the DME 100, instead ofbeing disconnected as described above with respect to FIGS. 10A and 10B.GPS antennas, for instance, are usually relatively wide and heavy, andwould be problematic to disconnect from the DME 100 upon impact.Accordingly, provided are various example retractable antenna systems1100, 1200, as shown in FIGS. 11A through 12C.

With reference to FIGS. 11A and 11B, provided is an example retractableantenna system 1100, comprising an antenna 1110 such as a GPS antennaretractably mounted to the DME structure 1140. In certain embodimentsGPS data is the primary signal used for guidance, navigation, andcontrol of the DME 100 and coordinating its movement with the subjectvehicle 650. For example, a GPS antenna 1110 may be mounted to aretractable member 1120, for instance to a top surface 1122 of aretractable member 1120, such that at least a portion of the GPS antenna1110 protrudes beyond the adjacent outer surface 1142 of the DMEstructure 1140 to facilitate communication with the antenna 1110. Thetop surface 1122 of the retractable member 1120 may be retractablybiased against the DME structure 1140 by one or more springs 1130connected with the DME structure 1140, such that when a downward forceis applied to the GPS antenna 1110, as when a subject vehicle 650 runsover the DME 100, the spring 1130 is compressed and GPS antenna 1110 andretractable member 1120 retract at least partially beneath the outersurface 1142 of the DME structure 1140, for instance as shown in FIG.11B. In the example shown in FIGS. 11A and 11B, a torsional spring 1130is provided on one side of the GPS antenna 1110 and retractable member1120, such that the GPS antenna 1110 and retractable member 1120 pivotabout the spring 1130 relative to the DME structure 1140. When thedownward force is removed from the GPS antenna 1110, the spring 1130biased against the retractable member 1120 urges the retractable member1120 and antenna 1110 to return toward their original position shown inFIG. 11A until the upper surface 1122 of the retractable member 1120re-engages the DME structure 1140, so that at least a portion of theantenna 1110 protrudes beyond the adjacent outer surface 1142 of the DMEstructure 1140 to facilitate communication with the antenna 1110.

Another example retractable antenna system 1200 is shown in FIGS. 12Athrough 12C. Like retractable antenna system 1100, retractable antennasystem 1200 comprises an antenna 1110 such as a GPS antenna retractablymounted to the DME structure 1140. Unlike retractable antenna system1100, retractable antenna system 1200 further comprises a GPS antenna1110 mounted to a multiple-pivot-point assembly of retractable members1220, 1225. For instance, retractable member 1220 may be retractablybiased against the DME structure 1140 by one or more springs 1230connected with the DME structure 1140, such that when a downward forceis applied to the GPS antenna 1110, as when a subject vehicle 650 runsover the DME 100, the spring 1230 is compressed and GPS antenna 1110 andretractable member 1220 retract at least partially beneath the outersurface 1142 of the DME structure 1140, for instance as shown in FIG.12B. Additionally, retractable member 1225 may be retractably biasedagainst the retractable member 1220 by one or more springs 1235connected with the retractable member 1220, such that when a downwardforce is applied to the GPS antenna 1110, as when a subject vehicle 650runs over the DME 100, the spring 1235 is compressed and GPS antenna1110 and retractable member 1225 retract at least partially beneath theouter surface 1142 of the DME structure 1140, for instance as shown inFIG. 12C. In the example shown in FIGS. 12A through 12C, torsionalspring 1230, 1235 are provided on each side of the GPS antenna 1110 andretractable members 1220, 1225, such that the GPS antenna 1110 andretractable member 1225 pivot about the spring 1230 relative to the DMEstructure 1140, and the GPS antenna 1110 and retractable member 1225pivot about the spring 1235 relative to the DME structure 1140. When thedownward force is removed from the GPS antenna 1110, the springs 1230,1235 biased against the retractable members 1220, 1225 urge theretractable members 1220, 1225 and antenna 1110 to return toward theiroriginal position shown in FIG. 12A until the upper surface of theretractable member 1220 re-engages the DME structure 1140 and the uppersurface of the retractable member 1225 re-engages the retractable member1220, so that at least a portion of the antenna 1110 protrudes beyondthe adjacent outer surface 1142 of the DME structure 1140 to facilitatecommunication with the antenna 1110. This type of design providesbi-directional retraction that tends to minimize damage to the antenna1110 while being forced into the DME 100 in either forward or rearwardimpacts.

In other embodiments, any other type of spring or similar actingmechanism may be provided that retractably urges the antenna 1110 beyondthe adjacent outer surface 1142 of the DME structure 1140 to facilitatecommunication with the antenna 1110, while deflecting downward uponimpact to reduce any possible large loads that would otherwise betransmitted through the antenna 1110 or antenna mount as would occurwith a hard-mounted antenna that protrudes above the upper surface 1142of the DME 100.

By limiting the forces on the antenna 1110, the present designs protectthe antenna 1110 from damage while eliminating the need for a break-awayconnector for GPS or other antenna types. In the case of GPS, thisimproves signal reliability and provides a robust and consistent signal.

6.7 Example Soft Collision Partners, Systems and Methods

The soft car body or Soft CP 600 as shown in FIGS. 6A through 6D isremovably mounted atop the DME 100 and is designed to minimize thepotential for damage to the body panels of the subject vehicle 650 thatimpacts the soft car body 600. The soft car body 600 can be designed toreplicate the three-dimensional shape and size of various objects, suchas light passenger vehicles. It may be constructed completely from“soft” materials, such as polyethylene foam, hook-and-loop closure andflexible epoxy, for instance. The panels are typically soft andflexible, formed from one or more uniformly-distributed materials havingan overall hardness no greater than 100 Shore OO. For example, thepanels of the soft car body 600 and internal structure may be fabricatedcompletely from light-weight, flexible and durable polyethylene foam,and may be connected to each other and to the DME 100 top surface by wayof hook-and-loop or any similarly-functioning reclosable fastenermaterial, such as 3M Dual Lock (3M trademark) reclosable fastenermaterial. This minimizes the risk of tearing individual panels, and alsoallows for quick reassembly after a collision with the subject vehicle650. The internal structure of the Soft CP 600 may be made up ofbulkheads that interconnect to form a framework for the outer skinpanels. These bulkheads can provide enough structural support for thebody panels under higher speed aerodynamic loading but are light andflexible relative to the subject vehicle 650, thereby minimizing theload imparted to the subject vehicle 650 body panels in the event of acollision. Instead of a Soft CP 600 as shown in FIGS. 6A through 6D, anyother shape may be attached to the DME 100 to form a GST, such as apedestrian shape 700, as shown in FIG. 7.

Example methods of using the example embodiment of FIGS. 21 through 31are shown in FIGS. 16 through 35. The presently disclosed Soft CP's maybe removably mounted atop a DME 100 and are designed to minimize thepotential for damage to the body panels of the subject vehicle 650 thatimpacts the Soft CP, such as the soft car bodies shown in FIGS. 16through 35. The soft car body can be designed to replicate thethree-dimensional shape and size of various objects, such as lightpassenger vehicles. It may be constructed completely from “soft”materials, such as polyethylene foam, hook-and-loop or similar closureand flexible epoxy, for instance. The panels of the soft car body andinternal structure may be fabricated completely from light-weight,flexible and durable polyethylene foam, and may be connected to eachother and to the top surface of the DME 100 by way of hook-and-loop orsimilarly functioning material. This minimizes the risk of tearingindividual panels, and also allows for quick reassembly after acollision with a subject vehicle (also known as a test vehicle), forinstance as shown in FIGS. 33 and 35. The internal structure of the SoftCP may be made up of bulkheads that interconnect to form a framework forouter skin panels or outer skin fabric. These bulkheads are adapted toprovide enough structural support for the body panels under higher speedaerodynamic loading but are preferably light and flexible relative tothe subject vehicle, thereby minimizing the load imparted to the subjectvehicle body panels in the event of a collision.

Examples of removably connectable structures 3000, 3100 are shown inFIGS. 30 and 31. With respect to FIG. 30, a Soft CP may comprise one ormore panels 3010, 3020, which may themselves be covered in fabric 3030,where the panels 3010, 3020 are constructed of polyethylene foam or anyother suitably strong and rigid yet soft and readily yielding material,which may be at least partially surrounded or encased in one or morefabric covers 3030. Fabric covers 3030 may be constructed from anysuitable material, such as canvas, and may provide abrasion resistanceand surface strength to resist the impact of a subject vehicle 650, andmay also provide connection surfaces for hook-and-loop or similarremovable fastening material 3040 and may provide surfaces forphotographic image printing and/or attachment of radar or other sensorreflective materials. Fabric covers 3030 may include one or moreportions 3045 extending away from the body of the panel 3010, whichportions or “tabs” 3045 are adapted to overlap with and removablyconnect to adjacent panels 3010, for instance with hook-and-loopmaterial, or any other suitable reclosable fastener material, as shownin FIG. 30. In the example embodiment shown in FIG. 30, the panelsinclude one or more internal bulkheads 3020, attached to andsubstantially covered by one or more fabric-wrapped foam skins 3010. Inthe example embodiment shown in FIG. 31, the fabric-wrapped foam skincoverings 3010 are replaced by fabric material or “skins” 3110.

FIGS. 23 through 28 depict example numbered panels that may be assembledas shown in FIG. 29 to produce the example embodiment Soft CP shown inFIGS. 16 through 22B. Each of the example panels shown in FIGS. 23through 28 may covered by the outside panels or fabric skins usingconnection systems as described above with respect to FIGS. 30 and 31.

Referring to FIG. 18, all the panels (Nos. 0 through 7) shown in FIGS.23 through 29, are shown in exploded view so that it is easy tovisualize the installations. Also shown in FIG. 18, are twolongitudinally-extending bulkhead panels 1805 which may be placedvertically atop the DME 100 or otherwise adjacent a desired structure.FIGS. 19 through 22B illustrate the assembly of the Soft CP. In FIG. 19one or more transversely-extending bulkhead panels may be placedvertically atop the DME 100 or otherwise adjacent a desired structure,and removably connected with the longitudinally-extending bulkheadpanels 1805 forming a framework with self-supporting structuralrigidity, as shown in FIG. 20. FIG. 21 depicts adding additional panelsthat help define the outer profile of the Soft CP, by removablyconnecting the additional panels with the longitudinally-extendingand/or transversely-extending bulkhead panels. These additional panelsmay be positioned in substantially vertical, horizontal or inclinedplanes, such as shown in FIG. 21. Then as shown in FIG. 22A, a fabricskin or fabric-wrapped foam skin may be positioned around the outerprofile of the panels described above, and removably connected thereto.In FIG. 22B the outer fabric skin or fabric-wrapped foam skin has beenfully installed and covers the internal panel network. All the removableconnections may be constructed and used as shown in FIG. 30 and/or 31,or using any other suitable structure that allows the panels and fabricto separate when impacted by a subject vehicle, and then be easilyre-assembled as shown in FIGS. 19 through 22B.

FIGS. 32 through 35 show the example embodiments of FIGS. 16 through 29in use. In FIG. 32, a subject vehicle 650 approaches from the left tothe right, while the example Soft CP 600, mounted atop a DME 100,approaches from the right to the left. The subject vehicle 650 and theSoft CP 600 are headed for a head-on, front-end to front-end collision.FIG. 33 shows what happens next: the front of the subject vehicle 650crashes into the front of the example Soft CP 600, and various panels ofthe Soft CP 600 separate from each other, allowing at least a portion ofthe subject vehicle to drive straight through at least a portion of theSoft CP 600 and, in this example, directly over the top of at least aportion of the DME 100.

In FIG. 34, a subject vehicle 650 approaches from the right to the left,while the example Soft CP 600, mounted atop a DME 100, also approachesfrom the right to the left, but at a slower speed or stopped. Thesubject vehicle 650 and the Soft CP 600 are headed for a front-end torear-end collision. FIG. 35 shows what happens next: the front of thesubject vehicle 650 crashes into the rear of the example Soft CP 600,and various panels of the Soft CP 600 separate from each other, allowingat least a portion of the subject vehicle 650 to drive straight throughat least a portion of the Soft CP 600 and, in this example, directlyover the top of at least a portion of the DME 100.

This new and improved Soft CP, system and method provides an inexpensiveand easy to assemble structure capable of closely simulating the rigidappearance and radar and other sensor signatures of items such as amotor vehicle, a pedestrian, or other object, while providing a safe andeasily reusable target for high-speed subject vehicles used to evaluatecrash avoidance technologies. Example Soft CP's designed, manufacturedand assembled according to the present invention can handle impacts suchas those shown in FIGS. 33 and 35 at relative speeds over 110 kilometersper hour without damage to the subject vehicle 650. The interlockinginternal structure of the Soft CP's as shown in FIGS. 33 and 35 providessufficient support to make the Soft CP's aerodynamically stable,limiting or eliminating aerodynamic flutter. The present Soft CP's canbe easily made to resemble the simulated item from all directions,allowing the subject vehicle 650 to approach from any angle whilegenerating accurate data. The Soft CP's may be calibrated against realvehicles or pedestrians in regard to their radar or other sensorsignatures. Instead of remaining in one piece that needs to be pushedout of the way, the present Soft CP's reduce impact forces by breakingapart into separate, light-weight, easily-to-reassemble panels, as shownin FIGS. 18 through 21. The present Soft CP's may be adapted for useatop low-profile drive systems that are driven-over by the subjectvehicle 650 as shown in FIGS. 33 and 35, instead of pushed out of theway by the subject vehicle 650. After the impacts, for instance as shownin FIGS. 33 and 35, the panels may be quickly and easily reassembled asshown in FIGS. 18 through 21.

Instead of a soft car as shown in FIGS. 16 through 35, any other shapemay be attached to a DME 100 to form a GST, such as a pedestrian shapeSoft CP, or a Soft CP of any other useful shape.

6.8 Example System Architectures and Functions

GST systems in various example embodiments may comprise, for instance, aplurality of computers that communicate, for instance via a WirelessLocal Area Network (WLAN), and perform various functions. FIG. 8illustrates the overall architectural layout of an example GST system800, which may include the following nodes and their associatedperipheral equipment, for example: a subject vehicle 650; base station850; and DME 100.

The computer associated with the subject vehicle 650 may perform thevarious data I/O functions within the subject vehicle 650, and providethe measured data to the rest of the system. Additionally, the subjectcomputer may control discrete events within the subject vehicle 650. Thesubject vehicle 650 node may comprise the following components, forexample: notebook computer; differential GPS receiver; tri-axialaccelerometer; digital I/O board to monitor and control discrete events(e.g., sense ACAT warning on/off, illuminate LEDs, initiate open-loopbraking, provide audible alerts); and wireless LAN bridge, for instance.

The base station 850 may act as the central hub for all communicationsand allow the operator to monitor and control the system. The basestation 850 may comprise the following components, for example:Differential GPS (DGPS) base station receiver; notebook computer;joystick; wireless LAN router; and radio transmitter to provideemergency-stop capability, for instance.

The computer associated with the base station 850 may allow the systemoperator to run a complete suite of tests from a single location. Fromthe computer associated with the base station 850, the operator mayperform the following functions, for example: setup and configuration ofsubject vehicle 650 and GST computers via remote connection; monitorsubject vehicle 650 and GST positions, speeds, system health informationand other system information; setup of test configuration; testcoordination; post-test data analysis; and selection of GST modes,including, for example: hold; manual; semi-autonomous; and fullyautonomous, for instance.

The DGPS receiver in the base station 850 may provide corrections to theroving DGPS receivers in both the DME 100 and the subject vehicle 650via a WLAN or other communications network. This may be accomplishedwithout the need for a separate DGPS radio modem, minimizing the numberof antennas on each node of the system. This may be important in thecase of the DME 100, since all connections to antennas are typicallymade frangible, such that they can separate from the DME 100 in theevent of a collision with the subject vehicle 650.

Example DME 100 subsystems may comprise the following components, amongothers, for instance: wireless LAN bridge; PC104 computer; yaw ratesensor; electronic compass; two brushless DC drive motors andamplifiers; a brushless DC steering motor and amplifier; brake system;RF emergency brake system; DGPS receiver; a DME computer such as a PC104computer that performs functions such as the following examplefunctions: Guidance, Navigation and Control (GNC) computations; analogand digital data input and output; inputs, including: differential GPSinformation; electronic compass (heading angle); yaw rate; drive motorspeed; steering angle; drive motor amplifier temperature; drive motorwinding temperature; and outputs, including: drive motor torque command;steer motor angle command; brake command; system health monitoring; anddata collection, for instance. Other or fewer components may be used invarious example embodiments.

6.9 Multiple-Frequency Data Transmission

As shown in the example network and system depicted in FIG. 8, two ormore separate communication systems may be provided between the DME 100and the operator's station 850. In one example embodiment, a firstcommunication system may use, for example, a 900 MHz, 1 W wireless LANto provide critical real-time data transfer between the subject vehicle650 and the DME 100 over longer ranges. A second communication systemmay use, for example, a 2.4 GHz (802.11b\g), 500 mW high-speed wirelessLAN for large data file transfers and setup/configuration of the DME 100over short distances, for instance prior to the start of a test.Additional communication systems may be provided, such as radio waveband systems for remote control signals. Increasing the transmissionpower will further increase the communication range. The exampleembodiment shown in FIG. 8 may increase the communication range overwhich the system can operate to approximately 1 km, whereas typicalprior art systems would lose communication at approximately 250 m.

It is critical that data packets not be lost during a test in order tomaintain coordination between the DME 100 and the subject vehicle 650.Separation of critical and non-critical data into two separatecommunication systems improves the reliability and performance of thecritical data transmissions, reducing data packet losses. Separation ofdata into multiple separate communication systems further allows thesystems to avoid interference-prone frequencies for certain tasks. Forexample, interference has been noted between 2.4 GHz transmissions andGPS antennas. Use of 900 MHz for critical real-time data eliminates thisas a concern for testing.

Certain frequencies are also better suited for certain tasks. Forexample, 900 MHz data is best used for low-speed, long-rangecommunications. This data is typically data that is required during thetest, where the data must be received in real-time and is used inreal-time for control or mode transitions. For instance, subject vehicleposition may be communicated at 900 MHz for real-time synchronization ofthe DME 100 with position of the subject vehicle 650. ACAT State mayalso be communicated at 900 MHz to trigger the end of thesynchronization mode such that the DME 100 will not react to the changesin the trajectory of the subject vehicle 650 caused by the ACATresponse. Base Station Commands may also be communicated at 900 MHz tochange the state of the DME 100, for example from “Run” to “Hold.”Subject vehicle triggers may be communicated at 900 MHz to allow datasynchronization between the DME 100, the subject vehicle 650, and anyadditional data recording devices. Additionally, DME Position and Statusmay be communicated at 900 MHz so the operator of the system 800 canmonitor in real-time the operation of the DME 100. While 900 MHz is usedas an example frequency, it is understood that any similarly-functioningfrequency may be used for these and similar tasks without departing fromthe spirit and scope of the invention.

In contrast, 2.4 GHz data is better suited for high speed, short rangecommunications, such as potentially massively large data transfersoccurring before or after a run. Sending such large amounts of data overa slower network would require significantly more time, sometimes hours.Accordingly, initialization data may be communicated at 2.4 GHz totransfer the parameter initialization file(s) and the trajectoryfile(s), which may define the run and operational parameters of the DME100, but do not change during operation. Likewise, remote login data maybe communicated at 2.4 GHz to remotely login to the computer in the DME100 in order to start the required software during start-up. Transfer ofrecorded data may also be suitable for communication at 2.4 GHz totransfer large data files that have been recorded on the computer in theDME 100. The transfer of such files would typically occur after thecompletion of one or more tests. While 2.4 GHz is used as an examplefrequency, it is understood that any similarly-functioning frequency maybe used for these and similar tasks without departing from the spiritand scope of the invention.

6.10 Method of GST Operation

Prior to testing, paired time-space trajectories for the subject vehicle650 and GST (e.g., a soft body 600, 700, mounted on a DME 100) may begenerated. These trajectories should be physics-based, and either can behypothetical or reconstructed real-world crash scenarios. Trajectoriescan be specified to result in any manner of collision between thesubject vehicle 650 and GST, and can include variations in speed andpath curvature for both the subject vehicle 650 and GST. The spatialtrajectories may be stored in files which also include subject vehicle650 and GST speeds along their respective paths, and scenario-specificdiscrete events. These discrete events (e.g., point of brakeapplication) can be used to control the timing of events in the subjectvehicle 650 at known points along the subject vehicle 650 path. Thesecan be used to initiate open-loop braking, illuminate LEDs, or provideaudible alerts within the subject vehicle 650, for example.

In various embodiments a GST system 800 may have, for instance, fourdifferent modes of operation: hold; manual; semi-autonomous; andfully-autonomous. The Hold Mode is the “idle” mode for the GST system.In this mode, the output signals to the steering and drive motors may benullified, but the GUI for the base station 850 may continue to showdata from the GST and subject vehicle 650 sensors. Whenever the GST isswitched into this mode from one of the “active” modes (e.g., Manual,Semi-Autonomous or Fully Autonomous), data that was collected during theactive mode may be transferred wirelessly to the computer associatedwith the base station 850 for further analysis.

The Manual Mode may be completely human-controlled via a joystickassociated with the base station 850. In this mode, the operator mayhave remote control over the speed and steering of the GST. This modemay be useful in pre-positioning the GST or for returning it to base forcharging the batteries, routine service, or for shutting down thesystem.

The Semi-Autonomous Mode allows the operator of the base station 850 tocontrol the speed of the GST while the path following may beaccomplished autonomously. This may be especially useful forpre-positioning the GST before a given test run, since the GST can bedriven starting from any point on the test surface, and it will seek andconverge on the desired path. The path-following GNC algorithm also mayallow for operation in reverse, allowing the operator to drive the GSTin reverse along the path for fast repetition of tests.

The Fully Autonomous Mode may require no further inputs from the basestation 850. In this mode, the subject vehicle 650 may be driven alongthe subject vehicle 650 path, and the GST computes the speed andsteering inputs necessary to move along its own path in coordinationwith the subject vehicle 650, as determined by the pre-programmedtrajectory pair. In this way, the longitudinal position of the GST maybe driven by the longitudinal position of the subject vehicle 650 suchthat the GST arrives at the pre-determined collision point at the samemoment as the subject vehicle 650, even accommodating errors in thespeed of the subject vehicle 650 (relative to the speed in thetrajectory file) as it approaches by adjusting its own speed. As anoption, the test engineer can enable a sub-mode in which, if the subjectvehicle 650 driver or ACAT system begins to react to the impendingcollision, the GST speed command may be switched to the speed containedin the trajectory file such that it is no longer dependent upon thespeed of the subject vehicle 650. The switch to this sub-mode may bemade automatically (mid-run) when the subject vehicle 650 accelerationexceeds a predetermined threshold (e.g., 0.3 g) or when subject vehicle650 ACAT system activation may be sensed via a discrete input. In thisway, the GST passes through the would-be collision point at the speedprescribed in the trajectory file, irrespective of the position or speedof the subject vehicle 650.

6.11 Testing with the GST

During test setup, the paired time-space trajectories may be wirelesslyloaded into the DME 100 on-board processor from the base station 850,and the GST may be placed into the fully autonomous mode. As the subjectvehicle 650 begins to travel along its path, its position (as measuredby differential GPS) may be transmitted wirelessly to the DME 100processor, which may be programmed to accomplish lateral andlongitudinal control to obtain the desired relative closed-looptrajectories. A given test run can culminate in a collision between thesubject vehicle 650 and the GST, as shown in FIG. 6D, in which case, theGST may be brought to a stop using a radio transmitter, separate fromthe WLAN, which can actuate the onboard brakes of the GST, and disablethe drive motors. Test data may be automatically transmitted wirelesslyfrom the DME 100 to the computer associated with the base station 850once the operator transitions from the Fully Autonomous mode to the Holdmode. The Soft Collision Partner 600 can then be reassembled on the DME100, usually within 10 minutes with a crew of two, and the GST can thenbe repositioned for the next run.

The GST may employ high-performance and high-efficiency components,allowing it to reach relatively high speeds and achieve high positionalaccuracy along its trajectory, both laterally and longitudinally.Brushless DC drive motors efficiently deliver high power from a smallpackage, and a Differential GPS receiver provides high positionalaccuracy. The GNC algorithm is able to utilize the capabilities of thesesensors and actuators to maximize the utility of the test methodology.

6.12 Results

A complete listing of GST performance specifications of exampleembodiments disclosed herein is shown below in Table 1.

TABLE 1 Example GST Performance Specifications Specification Value DGPSpositional accuracy 1 cm (depending on DGPS receiver) DME waypointaccuracy Lateral: 300 mm Longitudinal: 300 mm DME top speed (alone)  80km/h DME + Soft Car speed >55 km/h (demonstrated) Maximum closing speedat 110 km/h (demonstrated) impact Longitudinal acceleration ±0.3 gLongitudinal deceleration  −0.6 g under braking Lateral acceleration±0.3 g Distance traveled per battery 4 km at 40 km/h charge(theoretical) Remote control range  0.5 km Drive motor performance 2brushless DC drive motors, totaling: 30 kW peak  6 kW continuous Busvoltage 200 VDC Turning radius <3 m Visibility with Soft Car >0.5 kmbody, daylight Battery charge time 30-40 min (for full charge ofdepleted batteries) Soft Car reassembly time 10 minutes

The GST System 800 is a fully-functional and proven system forevaluating ACATs throughout the entire pre-conflict and conflictscenario up to the time of collision. By enabling the ACAT to beevaluated up to the time of collision, the GST System 800 allows themitigation capabilities of ACATs to be evaluated in a way that cannot beachieved via testing that does not involve actual collisions.Additionally, the DME 100 allows the evaluation of ACATs in conflictscenarios where the Soft CP is not static. The full-sized Soft CollisionPartner 600 allows evaluations of the ACAT in any crash configurationwithout requiring specific soft targets 600 for each configuration(e.g., rear-end soft targets).

As one example, the GST System 800 was used in the evaluation of aprototype Advanced Collision Mitigation Braking System. The system 800may be designed to alert the driver in the event of a likely collisionand to mitigate the collision severity through automatic application ofthe brakes for imminent collisions. The test matrix for this evaluationconsisted of thirty-three unique crash scenarios, representing fourdifferent crash types, repeated with and without the ACAT active. Thecrash types involved were: Pedestrian; Rear end; Head-on; and Crossingpath. During the course of testing, the GST was struck or run over bythe subject vehicle 650 more than sixty-five times without being damagedor causing damage to the subject vehicle 650.

By repeating the same conflict scenario with and without the ACATactive, the evaluation methodology allows the evaluator to determineboth the reduction in number of collisions due to the ACAT and thereduction in collision severity (i.e., closing speed, contact points,relative heading angle) when a collision occurs. Evaluation of thereduction in collision severity can be achieved because the subjectvehicle 650 and the GST positions and speeds may be continuouslyrecorded with high precision. Additionally, a more rigorous analysis ofthe collision severity in a given test can be achieved by determiningthe predicted collision delta-V (change in velocity) for each test byusing a multi-body crash simulation tool.

As will be apparent to persons skilled in the art, modifications andadaptations to the above-described example embodiments of the inventioncan be made without departing from the spirit and scope of theinvention, which is defined only by the following claims.

The invention claimed is:
 1. A break-away antenna system adapted for usewith a Guided Soft Target, comprising: an antenna adapted to mount to asoft body of a Guided Soft Target, the soft body removably attachable toa Dynamic Motion Element of the Guided Soft Target; first antenna wiringextending from the antenna; second antenna wiring extending from theDynamic Motion Element; a reattachable electrical connector adapted toelectrically connect the first antenna wiring with the second antennawiring sufficiently to maintain an uninterrupted electrical connectionduring normal use of the Guided Soft Target; the reattachable electricalconnector adapted to disconnect the first antenna wiring from the secondantenna wiring without damage to the connector or the first or secondantenna wiring when the soft body is suddenly removed from the DynamicMotion Element due to the Guided Soft Target being impacted by a subjectvehicle; wherein the reattachable electrical connector and secondantenna wiring is recessed below an exterior surface of the DynamicMotion Element.
 2. The break-away antenna system of claim 1, wherein theantenna extends beyond an exterior surface of the soft body when theantenna is mounted to the soft body.
 3. The break-away antenna system ofclaim 1, further comprising a plurality of said antennas with aplurality of first antenna wiring extending therefrom, one or more ofthe reattachable electrical connectors adapted to electrically connectthe plurality of first antenna wiring with the second antenna wiring. 4.The break-away antenna system of claim 1, wherein slack is provided inthe second antenna wiring.
 5. The break-away antenna system of claim 1,wherein the reattachable electrical connector comprises a standardBNC-type or TNC-type connector absent the locking structures normallypresent on such connectors.
 6. The break-away antenna system of claim 5,wherein the standard BNC-type or TNC-type connector comprises a smoothouter surface adapted to prevent catching on adjacent surfaces duringimpact.
 7. A break-away antenna assembly adapted for use with a GuidedSoft Target, comprising: an antenna mounted to a soft body of a GuidedSoft Target, the soft body removably attached to a Dynamic MotionElement of the Guided Soft Target; first antenna wiring extending fromthe antenna; second antenna wiring extending from the Dynamic MotionElement; a reattachable electrical connector electrically connecting thefirst antenna wiring with the second antenna wiring sufficiently tomaintain an uninterrupted electrical connection during normal use of theGuided Soft Target; the reattachable electrical connector adapted todisconnect the first antenna wiring from the second antenna wiringwithout damage to the connector or the first or second antenna wiringwhen the soft body is suddenly removed from the Dynamic Motion Elementdue to the Guided Soft Target being impacted by a subject vehicle;wherein the reattachable electrical connector and second antenna wiringis recessed below an exterior surface of the Dynamic Motion Element. 8.The break-away antenna assembly of claim 7, wherein the antenna extendsbeyond an exterior surface of the soft body.
 9. The break-away antennaassembly of claim 7, further comprising a plurality of said antennasmounted to the soft body with a plurality of first antenna wiringextending therefrom, one or more of the reattachable electricalconnectors electrically connecting the plurality of first antenna wiringwith the second antenna wiring.
 10. The break-away antenna assembly ofclaim 7, wherein slack is provided in the second antenna wiring.
 11. Thebreak-away antenna assembly of claim 7, wherein the reattachableelectrical connector comprises a standard BNC-type or TNC-type connectorabsent the locking structures normally present on such connectors. 12.The break-away antenna assembly of claim 11, wherein the standardBNC-type or TNC-type connector comprises a smooth outer surface adaptedto prevent catching on adjacent surfaces during impact.